that is to cool but how did you do it?
quite simple, go to the BBC Weather home page (http://"http://news.bbc.co.uk/weather/") and search for your city's forecast. On the page that proceeds, you will have a 5 day forecast widget with an "embed" button at the bottom. Click this and in the little pop-up window you will have an embed piece of code something like this:
<iframe src="http://news.bbc.co.uk/weather/forecast/8/Next3DaysEmbed.xhtml?target=_parent" allowTransparency="true" width="306" height="435" frameborder="0">You must have a browser that supports iframes to view the BBC weather forecast</iframe>
What you need is the url bit in quotes after the "src=" which you can put into the "website" bit of web item on your screen which should give you a 3 day forecast. There are other weather widgets which could do a similar thing with on the same page.
Hope that helps.
Also, note the height and width values provided! ;)